The present disclosure relates to an improved apparatus for producing a chilled or partially frozen beverage often referred to as a slush beverage. A variety of apparatus have been designed to produce chilled beverages as well as to produce beverages which are in slush form. Some of these apparatus are referred to as “granita” machines. Such apparatus can be used to produce slush beverages for a number of products including fruit juices, coffee-based beverages, tea-based beverages, dairy based beverages, as well as beverages containing alcohol. The apparatus include a chilling structure and some form of blade or auger which moves relative to the chilling portion to strip the frozen product off and circulate the beverage along the chilling portion. Circulation of the frozen beverage within the beverage hopper and along the chilling portion helps to reduce the temperature of the beverage mixture thereby causing the partially frozen beverage to approach a slush consistency. There is a need for an improved chilled beverage producing apparatus.
One problem with the prior frozen beverage apparatus is that the rotatable augers of such machines typically induce an “ice hump” condition within the beverage hopper in which frozen beverage product collecting at the top of the hopper toward its front end. This condition is most common during a “freeze down” mode of operation of the machine which occurs when a substantial quantity of warmed beverage in the beverage hopper is rapidly chilled to being it to a slush or partially frozen condition.
A “freeze down” event is defined for purposes of this application as the time period required to chill and mix a quantity of warmed liquid beverage within the beverage hopper until a partially frozen beverage of adequate serving quality can be dispensed. A “freeze down” events typically occurs either after (a) the machine is partially re-filled with beverage products during periods of heavy use, (b) it is reactivated from a “night mode” operation, or (c) the initial filling of the beverage hopper after cleaning. As the ice crystals are scraped off the chilling structure, they rise in the beverage hopper since the crystals are less dense than the warmed beverage in the lower portion of the hopper. At the same time those ice crystals are rising due to their buoyancy, they are also being pushed forward and upward by the action of the auger. In prior devices, the “ice hump” would typically break up after it becomes large enough to collapse under its own weight and to fall back into the lower portion of the container. This collapse can take a considerable period of time to occur. As a result, the formation of an “ice hump” substantially slows the time period required for the system to complete a “freeze down” event.
Another problem that arises is that the chilled beverage product can become less uniformly mixed within the beverage hopper than is desirable. This can cause inconsistencies in the frozen beverage product from serving to serving. Lack of uniform mixing with the prior rotatable augers is often due to stagnant areas forming within the beverage hopper which are not homogeneously mixed with the remainder of the frozen beverage. Typically, these stagnant corners further contribute to inconsistencies in the beverage product.
One prior attempt to deal with the problems of delayed freeze down and insufficient product mixing has been to provide a second auger or mixing mechanism for breaking up the “ice hump” or stagnant corners within the beverage. This approach has the drawback of increasing the cost of the frozen beverage machines, their complexity, as well as creating difficulties in servicing them. Such two auger machines also have a tendency to mix air into the partially frozen beverage which causes undesirable “frothing” of the product. It is one object of the invention to provide a cost efficient partially frozen beverage machine having an improved mixing apparatus and method for providing a more consistent frozen beverage product.
It is another object of the invention to provide an improved mixing apparatus and method of using same that substantially prevents the formation of an “ice hump” or rapidly breaks up any “ice hump” that begins to form thereby providing rapid completion of a “freeze down” event.
The present disclosure is directed to an improved apparatus for producing a partially frozen beverage which includes a beverage hopper for retaining a quantity of partially frozen beverage, a rotatable mixing member, a chilling unit for cooling the beverage within the hopper, a sensing member for detecting the occurrence of a rotation reversal condition, a controller for generating a rotation reversal signal, and a drive motor operably coupled to the rotatable mixing member for rotating the mixing member in a first direction during normal operation and in a second, reverse direction in response to a rotation reversal signal. The reverse rotation of the rotatable mixing member improves the efficiency of the mixing of partially frozen beverage within the beverage hopper and is effective in speeding the conclusion of a “freeze down” event relative to prior “forward rotation only” beverage apparatus. Further, the machines disclosed may be designed with a single mixing member, rather than the more costly multiple mixing member machines sometimes used with prior machines.
In one preferred embodiment of the present invention, the sensing member is programmed to detect a “freeze down” event of a certain duration as a rotation reversal condition. During this operation, the chilling unit is maintained below a pre-determined temperature for periods of greater than about ten (10) minutes. Such operation conditions are likely to produce an “ice hump.” Reversal of the rotatable member prevents or limits this occurrence by pulling ice crystals from the top-front portion of the machine and mixing them with the contents of the remainder of the beverage hopper. This causes more rapid “freeze down” of the beverage as complete mixing does not require waiting for collapse of the “ice hump” under its own weight. Where all or large portions of the beverage product is in liquid rather than partially frozen form, it may be necessary to cycle between forward rotation and reverse rotation repeatedly during a “freeze down” event. Preferably a torque sensor is also provided to sense the torque at the drive shaft of the drive motor. The torque sensor detects a torque valve that is correlated with a high quality product consistency. Once the selected torque value is detected, the flow of coolant into the chilling unit associated with beverage hopper is switched to an “off/ice” position. During the reverse rotation phase, the torque sensor is preferably deactivated so that it does not interfere with the operation of apparatus because reverse rotation may cause temporary fluctuations in measured torque which are not indicative of product quality.
In another preferred embodiment of the invention, the sensing member may be a timer that discerns that the rotatable mixing member has been rotating in a first direction for a pre-determined period of time that is indicative of incomplete mixing or stagnation in the corners of the beverage hopper. Reversal of the direction of rotation of the auger for a pre-determined period of time causes reverse circulation of the partially frozen beverage such that any stagnate frozen beverage is mixed with the remainder of the beverage. This results in a more homogeneously mixed frozen beverage product. Preferably, the timer is further programmed to detect a pre-determined period of reverse direction rotation. In response thereto, a forward rotation signal is generated and communicated to the drive motor. The drive motor is then caused to alter its rotation back into a normal, forward rotation mode until the pre-determined time period again lapses and a new reverse direction rotation cycle may be initiated.